Analytical Chemistry Commons^™

Intercalation Of Clo4- Into Hopg Investigated By Ec-Stm, Xiao-Yan Hu, Alice Aliwowe, Jia-Wei Yan, Bing-Wei Mao

Journal of Electrochemistry

The electrochemical intercalation and surface morphology of highly oriented pyrolytic graphite (HOPG) electrode in 2 mol⋅L^-1 HClO₄ were studied by in situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV). Based on the step-height changes observed before and after the intercalation, the effects of different step sites on intercalation are compared. The feasibility, reversibility and speed of intercalation are discussed. The intercalation ofClO₄^- into HOPG can be divided into three types depending on the number of graphite layers at the step site: When the layers of graphite are more than three, the intercalation becomes feasible; when …

Characterization Of Cytidylyltransferase Enzyme Activity Through High Performance Liquid Chromatography, James Brault

Theses and Dissertations

The cytidylyltransferases are a family of enzymes that utilize cytidine 5â?? triphosphate (CTP) to synthesize molecules that are precursors to membrane phospholipids. There are four well known enzymes: CTP: phosphoethanolamine cytidylyltransferase (ECT), CTP: glycerol-3-phosphate cytidylyltransferase (GCT), 2-C-methyl-D-erythritol-4-phosphate cytidylyltransferase synthetase (CMS), and CTP: phosphocholine cytidylyltransferase (CCT). Previously, a radioisotope tagging method was employed to study cytidylyltransferase catalysis. Using CCT as a model, a method utilizing high performance liquid chromatography (HPLC) was developed to replace the radioisotope scintillation technique. The development of this new HPLC method is cheaper, more efficient, and more accurate than the previously established method.

The targets of separation …

Electrochemical Formation Of One-Dimensional Metal Nanostructures Across Microgaps Electrodes For Resistive Switching And Optical Sensing Applications., Nidhi Shah

Electronic Theses and Dissertations

This dissertation focuses on the electrochemical formation of one-dimensional (1D) Ag nanostructures (in particular nanowires and nanochains) directly on electrode surfaces or gap of two electrodes. Ag nanowires (NWs) and nanorods (NRs) grow directly on glass/indium tin oxide (ITO) surfaces from electrode-attached Au nanoparticle seeds in the presence of cetyltrimethylammonium bromide (CTAB) at appropriate potentials with a 5-15 % yield and the average length ranging from 100 nm to 3 µm for growth times of 30 to 120 min. This method failed when trying to grow Ag NRs/NWs across 5 µm Au electrode gaps. Interestingly, applying voltage in air leads …

The Unique Electrochemical Reactivity Of Small Metal Nanoparticles., Rafael A. Masitas

Electronic Theses and Dissertations

This dissertation describes the factors controlling metal nanoparticle (NP) oxidation, using Au oxidation in Br- and Ag oxidation in acid as model systems. We found that the oxidation potential depends on size, surface charge, and electrode material. Size has a dramatic effect, shifting about 200 mV from > 200 nm diameter down to 4 nm diameter. The shift is more dramatic below 4 nm. 2.3 nm average diameter Au NPs oxidized in the 300-500 mV range and 1.5 nm average diameter Au NPs displayed several sharp peaks from 200 mV to as low as -200 mV. These smallest Au NPs show …

Applications Of High Performance Affinity Chromatography With High Capacity Stationary Phases Made By Entrapment, John A. Vargas Badilla

Department of Chemistry: Dissertations, Theses, and Student Research

High performance affinity chromatography (HPAC) is a technique that uses a biologically-related agent such as a transport protein or an antibody as the stationary phase in an HPLC system. In recent years, HPAC has been shown to be a valuable bioanalytical tool for studying solute-protein interactions. Human serum albumin (HSA), the most abundant protein in blood (with concentrations of 35 to 50 mg/mL in serum), has been shown to interact with many drugs, affecting their transport, excretion and metabolism. A physical method for immobilizing proteins in HPAC supports has been optimized in this dissertation by using HSA as a model …

Application Of Pd/Graphene Modified Electrode In The Detection Of 4-Chlorophenol, Peng Shi, Bo-Xuan Wang, Quan-Lin Song, Hui Wang, Xin Liu, Zhao-Yong Bian

Journal of Electrochemistry

The Pd/graphene composites were synthesized by a modified Hummers method and NaBH4 reduction process, and then were characterized using XRD, SEM, XPS, and TEM. The Pd/graphene modified glassy carbon electrode (Pd/graphene/GCE) was prepared based on this method. Cyclic voltammetry was used to study the optimum operation conditions for the 4-chlorophenol detection. It was shown that the surface of the graphene was smooth and Pd nanoparticles were uniformly dispersed on graphene. The average particle size was calculated to be 6.5 ± 0.05 nm. These nanoparticles exhibited high catalytic activity and sensitivity toward chlorophenols. PBS with a concentration of 0.1 mol·L^{-1 …}

Bis(Spirolactam) 1,3-Double-Armed Calix[4]Arene Compounds And Their Application As Extractants For The Determination Of Heavy Metal Ions, Fintan Kelleher, Mary Deasy, James Ward, Li Li, Fiona Regan

Articles

A number of double-armed calix[4]arene compounds, with proline-derived spirolactam ligating groups on the lower rim, have been synthesised and investigated as extractants of toxic heavy metal ions from aqueous solution. Pedersen’s extraction technique was employed to determine the capability of these new 1,3-distal derived calix[4]arene spiroalactams to extract selected heavy metal ions (e.g. Pb²⁺, Cd²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Co²⁺) from an aqueous phase into an organic phase. The percentage extraction was calculated using UV-vis spectroscopy. All of the compounds synthesised demonstrated good selectivity for the heavy metals selected …

Chemometric And Bioinformatic Analyses Of Cellular Biochemistry, Bradley Worley

Department of Chemistry: Dissertations, Theses, and Student Research

The amount of information collected and analyzed in biochemical and bioanalytical research has exploded over the last few decades, due in large part to the increasing availability of analytical instrumentation that yields information-rich spectra. Datasets from Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), infrared (IR) or Raman spectroscopy may easily carry tens to hundreds of thousands of potentially correlated variables observed from only a few samples, making the application of classical statistical methods inappropriate, if not impossible. Drawing useful biochemical conclusions from these unique sources of data requires the use of specialized multivariate data handling techniques.

Unfortunately, proper implementation of …

Small Molecule Inhibitor Design For Anaplastic Lymphoma Kinase Inhibition, Theodore D. Hansel, David J. Grabovsky

Interface Compendium of Student Work

The Anaplastic Lymphoma Kinase (ALK) gene has been linked to tumorigenesis in a number of human cancers, including anaplastic large cell lymphoma (ALCL) and neuroblastoma. While ALK mutations in ALCL and many other cancers occur as a result of gene fusions with wild type kinase domains, those in neuroblastoma stem from single nucleotide polymorphisms (SNPs) in the kinase domain. These lead to autophosphorylation and constitutive signaling by ALK for cell growth and division, ultimately causing cancer. Crizotinib, an ATP-competitive ALK inhibitor, has proven to be an effective inhibitor of both ALKWT and ALKMutant kinase domains, and is in the middle …

Distributed Approach For Peptide Identification, Naga V K Abhinav Vedanbhatla

Masters Theses & Specialist Projects

A crucial step in protein identification is peptide identification. The Peptide Spectrum Match (PSM) information set is enormous. Hence, it is a time-consuming procedure to work on a single machine. PSMs are situated by a cross connection, a factual score, or a probability that the match between the trial and speculative is right and original. This procedure takes quite a while to execute. So, there is demand for enhancement of the performance to handle extensive peptide information sets. Development of appropriate distributed frameworks are expected to lessen the processing time.

The designed framework uses a peptide handling algorithm named C-Ranker, …

Source-Specific Molecular Signatures For Light-Absorbing Organic Aerosols, Amanda Susan Willoughby

Chemistry & Biochemistry Theses & Dissertations

Organic aerosols (OA) are universally regarded as an important component of the atmosphere based on quantitative significance as well as the far-reaching impact they have on global climate forcing and human health. Despite the acknowledged importance, OA amounts and impacts remain the largest uncertainties regarding radiative forcing estimates. Incomplete chemical characterization of aerosol organic matter (OM) and a lack of concrete source apportionment is a major source of this uncertainty. The primary focus of this study is to provide much needed molecular details regarding ambient OA from key emission sources, and establish links between molecular and optical properties.

Complete chemical …

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O₃(g) by catechol γ_O3 = (7.49 ± 0.35) × 10^–6 occurs for …

Determination Of Triapine, A Ribonucleotide Reductase Inhibitor, In Human Plasma By Liquid Chromatography Tandem Mass Spectrometry, Ye Feng, Charles A. Kunos, Yan Xu

Chemistry Faculty Publications

Triapine is an inhibitor of ribonucleotide reductase (RNR). Studies have shown that triapine significantly decreases the activity of RNR and enhanced the radiation-mediated cytotoxicity in cervical and colon cancer. In this work, we have developed and validated a selective and sensitive LC-MS/MS method for the determination of triapine in human plasma. In this method, 2-[(3-fluoro-2-pyridinyl)methylene] hydrazinecarbothioamide (NSC 266749) was used as the internal standard (IS); plasma samples were prepared by deproteinization with acetonitrile; tripaine and the IS were separated on a Waters Xbridge Shield RP18 column (3.5 µm; 2.1 × 50 mm) using a mobile phase containing 25.0% methanol and …

Effect Of Adsorption Potential On Co Oxidation At Au@Pt Nanoparticles Electrodes, A Surface Enhanced Raman Spectroscopic Study, Pu Zhang, Yi Wei, Yong-Li Zheng, Yan-Xia Chen, Zhong-Qun Tian

Journal of Electrochemistry

The adsorption/oxidation of CO on the 55 nm [email protected] nm Pt nanoparticles electrode in both potentiodynamic and potentiostatic modes were investigated by surface enhanced Raman spectroscopy in a thin layer electrochemical flow cell under controlled mass transport, with the aim of clarifying the origin CO oxidation at lower electrode potentials (in current pre-wave region of corresponding cyclic voltammograms). Our results demonstrated that the CO oxidation kinetics differed significantly from the three kinds of different CO adsorption history, with almost no CO oxidation current in the pre-peak potential region after 0.35 V_RHE CO adsorption with or without subsequent holding the …

Broadband Sum-Frequency Generation Spectroscopic Invstigations Of Thiocyanate On Polycrystalline Au Electrode In Alkaline Solutions, Mei Xu, Jing-Jing Wang, Zhi-Chao Huangfu, Ng Ying Wa, Yu-Han He, Zhao-Hui Wang

Journal of Electrochemistry

Broadband sum frequency generation (BB-SFG) spectroscopy has been used to investigating the potential-dependent adsorption behaviors of thiocyanate ions on polycrystalline Au electrode in alkaline solutions. During the positive scan, a change in the Stark slope (dω_C-N/dE) for C—N stretching mode can be observed in the range of -1.1 V ~ 0.2 V (vs. SCE), which implies that the orientation of adsorbed thiocyanate ions at Au electrode surface changes from N-bound (dω_C-N/dE=45 cm^-1·V^-1) form to S-bound (dω_C-N/dE = 16.2 cm^-1·V^{-1 …}

Fluorinated Metallo Phthalocyanines For Chemical And Biological Catalysis, Hemantbhai H. Patel

Seton Hall University Dissertations and Theses (ETDs)

The rational design of robust oxidation catalysts based on organic molecules is hindered by the presence of labile C-H bonds. We have shown recently that replacing all C-H bonds by a combination of fluoro- and perfluoro-groups in a bioinspired Cytochrome P450 model based on a phthalocyanine, Pc, scaffold results in a stable yet reactive oxidation catalyst. The Pc cobalt complex catalyzes, for example, the aerobic oxidation of thiols to disulfides, a reaction of both biological significance and industrial importance.

The presence of robust C-F bonds, however, renders the catalyst unsuitable for attachment to solid-state supports, except via van der Waals …

Applications Of Green Chemistry In Asymmetric Transfer Hydrogenation And Chiral Separations, Ruoqiu Wu

Seton Hall University Dissertations and Theses (ETDs)

Green chemistry has been applied to all aspects of the life cycle of chemically related products, including design, usage, manufacturing, analysis, and disposal. In this thesis, I focus on the green chemistry applications in organic synthesis and analytical chemistry. More specifically, allylic and chiral alcohols are abundant in natural sources such as in essential oils, and widely utilized as starting materials. They are also major components in food, fragrance, biocides and the pharmaceutical compounds. In this thesis, I report the first Ru-catalysed asymmetric transfer hydrogenation (ATH) of prochiral allylic alcohols. This reaction provides chiral secondary alcohols in excellent enantioselectivities and …

Evaluation Of 5 Μm Superficially Porous Particles For Capillary And Microfluidic Lc Columns, James Grinias, Robert T. Kennedy

College of Science & Mathematics Departmental Research

Large-size (4–5 µm) superficially porous particles yield lower plate heights (e.g., the minimal reduced plate height or h_min ≈ 1.5) than fully porous particles of a similar size when packed into large-bore columns. This property allows for better chromatographic performance without the higher pressures required for smaller particles. This study explores the use of such particles in microfluidic LC columns where materials and fitting pressure limits can constrain the size of particle used. The theoretically predicted performance improvements compared to fully porous particles were not demonstrated in capillary columns (with h_min ≈ 2 for both particle types), in …

Effect Of Surface Omniphobicity On Drying By Forced Convection, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Low energy surfaces can strongly repel both oil and water. Recently these surfaces have been fabricated on various substrates including fabric, aluminum, stainless steel and many other materials. In this experiment we explore the use of low energy surface deposition on aluminum alloy, stainless steel and silicon substrates, to enhance the drying rate of liquids removed from the surface by forced convection. We control surface roughness by substrate abrasion and by the growth of Al₂O₃ nanograss to enhance liquid repellence by use of a hierarchical texture. Liquid repellence of the substrates is measured by contact angles of …

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert

Chemistry Faculty Publications

Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing …

Linkage Analysis And Compositional Studies Of Β-Glucan From Saccharomyces Cerevisiae And Compositional Studies Of Mannan From Candida Albicans, Clara Arthur

Electronic Theses and Dissertations

The efficacy of a novel carbohydrate extraction procedure was investigated with methylation analysis and alditol acetate method by Gas Chromatography-Mass Spectrometry. A published extraction procedure for β-glucans was compared to one developed in house. Both procedures gave a dominant glucose peak in the Gas chromatogram indicative of successful β-glucan isolation. Further linkage studies showed four linkage positions for β-glucans isolated with the published method; terminal, 1,3-linkage, 1,6-linkage and 1,3,6-linkage, while β-glucans isolated using the new method showed six linkage positions; terminal, 1,3-linkage, 1,6-linkage, 1,4-linkage, 1,2,3-linkage and 1,3,6-linkage. Diminishing β-glucan linkage peaks in the chromatogram for the published method indicated structure …

Impurity Diffusion As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics, Edward T. Peskie, Howard L. Hall

International Journal of Nuclear Security

The ability to determine the age of seized nuclear material—that is, the time that has passed since it was formed— would provide crucial data to be used in its investigation. This paper reviews the methods and mathematical reasoning behind the use of diffusion theory, as previously applied to analysis of metals in ancient artifacts and other objects, to modern investigations in nuclear science. We here examine the time-dependent processes of diffusion, including grain boundary diffusion and discontinuous precipitation, and we assess the utility of examining the profiles of impurity and alloying element concentrations for use as a tool in pre-detonation …

Determining % Proliss 100 In Keratin Mousse Using Iodine Solution Method, Quiana Moore

All Capstone Projects

The objective of this experiment is to quantitatively determine the amount of active raw material Proliss 100 manufactured and supplied by a formulation company. The goal is to reproduce the percent of Proliss in Keratin Mousse production sample provided to consumers and provide measurements to be used to assess the accuracy of production with comparison to provided percent formulation for each batch. An iodine solution titration method was performed for this experiment due to the reduction-oxidation reactivity of the Proliss 100. This experiment is still undergoing further testing due to the confidentiality agreement between the manufacturer and formulator.

Artificial Maturation Studies Of Polymethylenic Plant Biopolymers: Investigating The Chemical Alterations From Plant Material To Coal, Blaine Elizabeth Hartman

Chemistry & Biochemistry Theses & Dissertations

The thermal maturation and alternation of vascular plant material into coals and as expelled petroleum-like compounds is the main focus of this dissertation. Utilizing artificial maturation studies, like hydrothermal liquefaction, yields useful information regarding how plant material is preserved in coals and the potential certain plant biopolymers possess to generate liquid fuels is acquired. The studies within this dissertation focus on utilizing the aliphatic biopolymers, cutin, cutan, and suberan, found in the epidermis of certain plants. These biopolymers contain minimal amounts of heteroatoms and are comprised of long polymethylenic chains, which are desirable characteristics in generating bio-oils. Additionally, understanding the …

Fundamental Studies Of Magnetoconvective Forces And Density Gradients In A Microfluidic Environment, Adam James Kreidermacher

Graduate Theses and Dissertations

Magnetoconvection is a promising phenomenon for developing new electrochemical-based microfluidic flow devices with unique capabilities, such as easily switching flow direction and adjusting flow speeds and flow patterns as well as avoiding bubble formation. In order to develop these devices it is necessary to study the underlying forces. Four contributions toward fluid flow were considered. The first and foremost is the magnetohydrodynamic force, which is the magnetic component of the Lorentz force and governed by the right hand rule. It generates the majority of the convention, and is the most well-known. The second is the gravitational force, which causes convection …

In Vitro Microdialysis Sampling Collection Of Volatile Organic Compounds (Voc's), Dodecafluoropentane (Ddfp) And Isoflurane, Valerie Shannon Mckinney

Graduate Theses and Dissertations

Death by stroke occurs every four minutes to human beings. Strokes cause necrosis within the tissue of the brain due to deprivation of oxygen. Perfluorocarbons have the ability to transport oxygen to tissue and in return decrease cell death. Dodecafluoropentane (DDFP) is a volatile fluorocarbon and collection in vivo can be a challenge since this compound evaporates at room temperature. There is currently not an efficient collection method in vivo for compounds that are volatile. Without a method to collect DDFP it is impossible to be approved for clinical use since exact concentrations of the drug within the body will …

The Best Of Both Worlds: Building On The Copus And Rtop Observation Protocols To Easily And Reliably Measure Various Levels Of Reformed Instructional Practice, Travis J. Lund, Matthew Pilarz, Jonathan B. Velasco, Devasmita Chakraverty, Kaitlyn Rosploch, Molly Undersander, Marilyne Stains

Department of Chemistry: Faculty Publications

Researchers, university administrators, and faculty members are increasingly interested in measuring and describing instructional practices provided in science, technology, engineering, and mathematics (STEM) courses at the college level. Specifically, there is keen interest in comparing instructional practices between courses, monitoring changes over time, and mapping observed practices to research-based teaching. While increasingly common observation protocols (Reformed Teaching Observation Protocol [RTOP] and Classroom Observation Protocol in Undergraduate STEM [COPUS]) at the postsecondary level help achieve some of these goals, they also suffer from weaknesses that limit their applicability. In this study, we leverage the strengths of these protocols to provide an …

The Investigation Of The Low Temperature Combustion Of Mesitylene And Tert-Amyl Methyl Ether By Synchrotron Photoionization Mass Spectrometry, Martin Yu-Hin Ng

Master's Theses

This thesis describes the combustion experiments performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) located at the Lawrence Berkeley National Laboratories (LBNL). The need for renewable fuel sources, the need for the study of their combustion in the contexts of homogenous charge combustion ignition (HCCI) engines can be found in Chapter 1. The components of the experimental set-up used throughout this thesis—time-of-flight mass spectrometer, Excimer laser, vacuum pumps and other components—and the components of ALS responsible in synchrotron radiation generation and processing—the linear accelerator, the booster ring, insertion devices, gas filters and monochromator are explained in …

Nanodiamond Extraction At A Potential Impact Location, Joel Kathan

DePaul Discoveries

Meteoritic or cometary impacts create the temperature and pressure conditions necessary to form nanodiamonds (NDs). The presence of extracted NDs from rocks of the time and locations of extinctions, fires, or known environmental changes are commonly used to confirm that a theorized cosmic impact occurred to trigger those events. Samples were obtained from an archeological site described in the Old Testament of the Bible as having been destroyed by the God of the Old Testament.† To see if the historical description of Biblical events might have been triggered by a cometary impact or explosion, an attempt was made to …

Diol-Mediated Versus Water-Mediated Proton Transfer Reactions, Angela Moses

DePaul Discoveries

The triple-proton-transfer reactions of 8H-1,8-naphthyridin-2-one (8H-naph) have been investigated by employing different ab initio quantum mechanical methods. The proton transfer reactions studied were facilitated through an adjacent 1,3-propanediol molecule or two adjacent water molecules. Identical proton transfer reactions were studied using a model system of 8H-naph to investigate the validity of computational approaches that use model systems to study more complex systems. The solvent effects on the structures were investigated for comparison to the initial gas phase calculations. The potential energy, reaction force, and work profiles were studied along the intrinsic reaction coordinate to monitor the developing proton transfer reactions.